Title

Authors

Date of this Version

November 1979

Abstract

Sea gulls (Laridae) of various species are more frequently reported in bird-aircraft collisions than any other group of birds. Various sources (Thorpe, 1976; Salter, 1976; Blokpoel, 1976) report that gulls were involved in 40 to 60% of all bird strikes for both civilian and military aircraft. A majority of these incidents occurred during landing or takeoff in the immediate vicinity of the airport. Thus, reducing the number of gulls in operationally critical areas of the airport is an important goal for flight safety manage- ment. Sea gulls at Langley Air Force Base (Harrison and Godsey, 1976) and other airports (Blokpoel, 1976) seek loafing areas which are visually unobstructed. The extensive pavement around airport runways provides large areas where gulls can loaf with a clear view of surrounding areas. Shallow pools of freshwater, found around poorly drained air- ports after a rainstorm, provide additional strong attractants. Food sources, such as organic refuse, insects, worms or other soil organisms provide even stronger attrac- tants to gulls. Procedures that reduce the attractiveness of airports to gulls and other birds have been reviewed extensively in other sources (e.g. Blokpoel, 1976; Wright, 1968). It has been generally noted (Saul, 1967; Stout et al., 1975) that gulls can be more easily dispersed from sites that have been made less attractive. Stout et al. (1975) observed that gulls were more difficult to disperse from natural sites where the gull's site tenacity was greater. For example, gulls which were dispersed from their reproductive territories by playing back distress calls returned almost immediately, and habituated very rapidly to repetitions of the call. Gulls along the seashore were more difficult to disperse than those that loafed along a runway less than 100 yards from the seashore. Gulls actively feeding at a dump were also more difficult to disperse than those that loafed in large, flat areas several hundred feet from the organic refuse source. All dispersal procedures for sea gulls are less successful in areas where environmental and/or behavioral factors increase the gulls' site tenacity.